Hepatitis C virus (“HCV”) infection is a common cause of viral hepatitis. It is estimated that 3% of the world's population is infected with HCV. (Clarke, B. E., Balliere's Clinical Gastroenterology, 14, No. 2, pp. 293-305 (2000). Until recently, alpha-interferon was the first therapy with proven benefit for treating HCV infection. Depletion of cellular guanine nucleotide reservoirs via inhibition of the NAD+-dependent enzyme, inosine monophosphate dehydrogenase (“IMPDH”), which is the rate-limiting enzyme in the de novo nucleotide biosynthesis, has been identified as an attractive target for anti-HCV therapy. See, VX-497, Drugs of the Future, 25(8), pp. 809-814 (2000). Known inhibitors of IMPDH include Ribavirin, VX-497, mycophenolate mofetil (CELLCEPT®), tiazofurin and mizoribine. Recently, a combination therapy, using alpha-interferon and Ribavirin™, has shown greater efficacy in treating HCV infection than a monotherapy using either entity. However, the combination therapy is not problem free. Alpha interferon is known to cause side effects such as high fevers, headaches, nausea and depression. Ribavirin tends to increase these side effects, and also cause haemolytic anaemia. Hepatologists are reluctant to reduce the dosage of Ribavirin below 800 mg/day (see, Foster, G. R. and Thomas, H. C., Balliere's Clinical Gastroenterology, 14(2), pp. 255-264 (2000). The minimum effective dose of Ribavirin is not yet known.
Thus, there is a need for a therapy that takes advantage of the synergy and/or additivity observed between alpha-interferon and an IMPDH inhibitor in the combination therapy, but preferably without the drawbacks associated with the individual components of the combination therapy.
Thus, there is a need for an optimal composition for treating HCV infection in a human, comprising alpha-interferon and an IMPDH inhibitor.
There is also a need for a method for treating HCV infection in a human comprising the step of administering to said human an optimal composition comprising alpha-interferon and an IMPDH inhibitor.
There is also a need for a method for evaluating the suitability of a composition comprising an IMPDH inhibitor and alpha-interferon for optimally treating HCV infection in a human.
There is also a need for a method of producing an optimal composition for treating HCV infection in a human, wherein said optimal composition comprises alpha-interferon and an IMPDH inhibitor.